Plasma processing apparatus, power source system, and plasma processing method
A plasma processing apparatus including a plasma processing chamber, a substrate support that is provided in the plasma processing chamber and on which a substrate is placed, a gas supply for supplying a processing gas to the plasma processing chamber, an RF power source for supplying pulsed RF power to the plasma processing chamber and/or the substrate support, and forming plasma from the processing gas, and a circuitry for controlling the supply of the pulsed RF power, in which the control device controls the RF power source such that an increasing function of a power level from a supply starting point of the pulsed RF power to a peak appearing point is a downward convex function, and/or a decreasing function of a power level from a peak ending point of the pulsed RF power to a supply ending point is a downward convex function.
1 . A plasma processing apparatus comprising:
a plasma processing chamber,
a substrate support provided in the plasma processing chamber and configured to receive a substrate,
a gas supply configured to supply a processing gas to the plasma processing chamber,
an RF power source configured to:
supply pulsed RF power to the plasma processing chamber and/or the substrate support, and
form plasma from the processing gas, and
circuitry configured to control the supply of the pulsed RF power by controlling the RF power source such that an increasing function of a power level from a supply starting point of the pulsed RF power to a peak appearing point is an upward concave function, and/or a decreasing function of the power level from a peak ending point of the pulsed RF power to a supply ending point is an upward concave function,
wherein the circuitry controls the RF power source such that the increasing function of the power level from the supply starting point of the RF power to the peak appearing point satisfies functions in the following formulas (1) and (2), in which a level of the RF power at the supply starting point of the RF power is defined as A,
in a case where A≠0,
Pw
(
t
)
=
A
exp
(
at
)
(
1
)
a
=
ln
(
P
max
/
A
)
/
t
max
(
2
)
in a case where A=0,
Pw
(
t
)
=
exp
(
at
)
-
1
(
1
)
a
=
ln
(
P
max
+
1
)
/
t
max
(
2
)
t indicates a time after the supply starting point of the RF power, Pw(t) indicates a level of the RF power at the time t after the supply starting point, Pmax indicates a peak value (a maximum value) of the level of the RF power, and tmax indicates a period from the supply starting point of the RF power to the peak appearing point, or
wherein the circuitry controls the RF power source such that the decreasing function of the power level from the peak ending point of the RF power to the supply ending point satisfies functions in the following formulas (3) and (4), in which a level of the RF power at the peak ending point of the RF power is defined as B,
Pw
(
t
)
=
B
exp
(
bt
)
(
3
)
b
=
ln
(
P
min
/
B
)
/
t
max
(
4
)
t indicates a time after the peak ending point of the RF power, Pw(t) indicates a level of the RF power at the time t after the peak ending point, P min indicates a minimum value of the level of the RF power, and t max indicates a period from the peak ending point to the supply ending point.
2 . The plasma processing apparatus according to claim 1 , wherein
the RF power is source RF power supplied to the plasma processing chamber or to the substrate support, and/or the RF power is bias RF power supplied to the substrate support.
3 . A power source system used in a plasma processing apparatus including a plasma processing chamber and a substrate support, the power source system comprising:
an RF power source configured to:
supply pulsed RF power to the plasma processing chamber and/or the substrate support, and
form plasma from a processing gas, and
circuitry configured to control the supply of the pulsed RF power by controlling the RF power source such that an increasing function of a power level from a supply starting point of the pulsed RF power to a peak appearing point is an upward concave function, and/or the decreasing function of a power level from a peak ending point of the pulsed RF power to a supply ending point is an upward concave function,
wherein the circuitry controls the RF power source such that the increasing function of the power level from the supply starting point of the RF power to the peak appearing point satisfies functions in the following formulas (1) and (2), in which a level of the RF power at the supply starting point of the RF power is defined as A,
in a case where A≠0,
Pw
(
t
)
=
A
exp
(
at
)
(
1
)
a
=
ln
(
P
max
/
A
)
/
t
max
(
2
)
in a case where A=0,
Pw
(
t
)
=
exp
(
at
)
-
1
(
1
)
a
=
ln
(
P
max
+
1
)
/
t
max
(
2
)
t indicates a time after the supply starting point of the RF power, Pw(t) indicates a level of the RF power at the time t after the supply starting point, Pmax indicates a peak value (a maximum value) of the level of the RF power, and t max indicates a period from the supply starting point of the RF power to the peak appearing point, or
wherein the circuitry controls the RF power source such that the decreasing function of the power level from the peak ending point of the RF power to the supply ending point satisfies functions in the following formulas (3) and (4), in which a level of the RF power at the peak ending point of the RF power is defined as B,
Pw
(
t
)
=
B
exp
(
bt
)
(
3
)
b
=
ln
(
P
max
/
B
)
/
t
max
(
4
)
t indicates a time after the peak ending point of the RF power, Pw(t) indicates a level of the RF power at the time t after the peak ending point, P min indicates a minimum value of the level of the RF power, and t max indicates a period from the peak ending point to the supply ending point.
4 . The power source system according to claim 3 , wherein
the RF power is source RF power supplied to the plasma processing chamber or to the substrate support, and/or the RF power is bias RF power supplied to the substrate support.
5 . A plasma processing method performed by a plasma processing apparatus,
the plasma processing apparatus including:
a plasma processing chamber,
a substrate support provided in the plasma processing chamber, the substrate support configured to receive a substrate,
a gas supply configured to supply a processing gas to the plasma processing chamber, and
an RF power source configured to:
supply pulsed RF power to the plasma processing chamber and/or the substrate support, and
form plasma from the processing gas,
the plasma processing method comprising:
preparing the substrate on the substrate support and processing the substrate using the plasma formed from the processing gas, and
controlling the RF power source such that an increasing function of a power level from a supply starting point of the pulsed RF power to a peak appearing point is an upward concave function, and/or a decreasing function of the power level from a peak ending point of the pulsed RF power to a supply ending point is an upward concave function,
wherein the RF power source is controlled such that the increasing function of the power level from the supply starting point of the RF power to the peak appearing point satisfies functions in the following formulas (1) and (2), in which a level of the RF power at the supply starting point of the RF power is defined as A,
in a case where A≠0,
Pw
(
t
)
=
A
exp
(
at
)
(
1
)
a
=
ln
(
P
max
/
A
)
/
t
max
(
2
)
in a case where A=0,
Pw
(
t
)
=
exp
(
at
)
-
1
(
1
)
a
=
ln
(
P
max
+
1
)
/
t
max
(
2
)
t indicates a time after the supply starting point of the RF power, Pw(t) indicates a level of the RF power at the time t after the supply starting point, P max indicates a peak value (a maximum value) of the level of the RF power, and t max indicates a period from the supply starting point of the RF power to the peak appearing point, or
wherein the RF power source is controlled such that the decreasing function of the power level from the peak ending point of the RF power to the supply ending point satisfies functions in the following formulas (3) and (4), in which a level of the RF power at the peak ending point of the RF power is defined as B,
Pw
(
t
)
=
B
exp
(
bt
)
(
3
)
b
=
ln
(
P
max
/
B
)
/
t
max
(
4
)
t indicates a time after the peak ending point of the RF power, Pw(t) indicates a level of the RF power at the time t after the peak ending point, P min indicates a minimum value of the level of the RF power, and t max indicates a period from the peak ending point to the supply ending point.
6 . The plasma processing method according to claim 5 , wherein
the RF power is source RF power supplied to the plasma processing chamber or to the substrate support, and/or the RF power is bias RF power supplied to the substrate support.